The Mindful Hack is a Web log of Denyse O'Leary, co-author of The Spiritual Brain: A neuroscientist's case for the existence of the soul (HarperOne August 2007). The Mindful Hack publishes information of interest on the relationship between the mind and the brain. O'Leary also publishes the Post-Darwinist, which keeps up with the intelligent design controversy.

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Sunday, January 09, 2011

Disgust: Psychologists wrestle with explanations

"In Tierra del Fuego a native touched with his fingers some cold preserved meat which I was eating at our bivouac, and plainly showed utter disgust at its softness; whilst I felt utter disgust at my food being touched by a naked savage, though his hands did not appear dirty."

As Darwin discovered, while we may differ about what evokes the response, disgust is one of the few universally shared human emotions. The native was expressing what psychologists call "core disgust." Unlike animals, which instinctively seek out certain foods, humans have to learn what to eat and are justifiably cautious about sampling new foods. Since Darwin’s cold, soft piece of preserved meat had a tactile resemblance to animal feces, the native was understandably disgusted by the thought of eating it. The revulsion was triggered by the idea that "like produces like"; since the preserved meat had many similarities to feces, the native assumed it might be similarly contaminated.

Darwin's unease was also based on a variation of the same core disgust. While his dinner companion worried that an object (the meat) could be contaminated because of its similarity to another object (feces), Darwin feared the contagion could be spread by contact with the native.

Carter discounts Darwin's natural selection as providing an explanation for the obvious reason that children learn disgust - and they learn disgust for whatever they are taught to. For example, whereas typical non-Muslim Canadian children are accustomed to "hero" police dogs, a British force had to apologize for using a puppy mascot due to British Muslim disapproval.

Carter notes,

In the seminal psychological research paper "Body, Psyche, and Culture: The Relationship Between Disgust and Morality", Jonathan Haidt and his coauthors note that disgusting events remind us of our animal nature. Because we feel the need to hide these markers of our kinship to lower creatures, we develop humanizing rituals and practices.

Now, that all sounds way off the track to me. First, anyone who has lived with a cat knows that cats are well able to express disgust, and I am sure that many other intelligent animals do the same, though their methods of expressing it might require some interpretation. They reject things that promise unpleasantness without being obviously dangerous. That's disgust.

Second, disgust for human behaviour often involves issues well beyond the reach of animals. Consider how we tend to feel about Saruman, for example, who tries to sell out his multi-intelligent species civilization to gain a foothold of power in an almost unthinkable barbarism. Disgust, yes, but "animal" doesn't come to mind. Going from bad to worse, he ends as a fist-shaped column of smoke somewhere, not as a jellyfish or rodent.